UM18 DIY Sub Build

Discussion in 'DIY Speakers and Subwoofers' started by LuisV, May 7, 2016.

  1. #1 LuisV, May 7, 2016
    Last edited: May 16, 2016
    Although my HSU VTF-15H sounds great, I always craved for more impact and deeper extension. After researching I decided on the Dayton UM18-22 driver and a Crown XLS 2502 amp so I placed my order. I originally planned on building a MiniMarty, but after I cut the MDF and performed a dry fit test in the room (not dedicated), my wife wasn't so pleased with a mini-fridge in the room, so I had to compromise. I would continue the marty build, but would also pick up a sealed flat pack and test both in the room. I figured, worse case I'm out the money spent buying the MDF I bought at Home Depot or will need to find a new location for the flat pack... upgrade the home office 2.1 stereo system perhaps? :cool:

    UM18 compared to the 15" driver from the HSU VTF-15H


    You just gotta love the flat packs as they are so easy to build. Over the course of 3 - 4 days, my son and I started the build and we let the glue or PL Premium dry over night before moving on to the next steps. We used PL Premium (construction adhesive) to seal the inside seams and to attach the driver cut out panel to the cabinet. We then drizzled glue over the entire cut out panel and with a scrap piece of wood we made sure there was a good thick even coat of glue over the entire panel. We then placed the top baffle on and clamped it in place. From the looks of all of the glue run out, we should have a good seal between these panels. :)

    11019529-2F48-4D3C-ADC4-96CC40DCD74F.jpg A02ADFEC-0911-40C0-A965-D53EF59F780F.jpg

    After letting the glue and clamps work their magic over night, we scraped and sanded the glue out and most seams are perfect. Since the front baffle came with a 1/2" round over, we used the same size bit to round the rest of the edges.

    IMG_6227.jpg IMG_6228.jpg

    We gave the driver recess a quick shot of flat black spray paint so when the driver is installed bare MDF won't be visible. After the dust settled from cleaning up the garage, we dusted the cabinet with a tack cloth and ran the wet / dry vac around the inside to pick up any left over. We then brought the cabinet inside and applied the 1st coat of Restore 4X. :)

    It needs another coat or two of Restore 4X, but before we do the second coat, we drilled the hole for the neutrik connector and sanded down some of the Restore 4x high spots. Getting close!

    We gave it a total of 3 coats of Restore 4x and I think it came out rather nice. We like the Restore 4X better than the Duratex. We stuffed the cabinet with about 4lbs of polyfil and we took it for a quick test run. All I can say is that I'm glad I gave DIY a try... can't wait to feel what this bad boy can do after it's in it's proper location and we do some tweaking with a MiniDSP. I'm already priming the wife about the MiniMarty and possibly a mid-bass module (or two) behind the couch.  :cool:


    Just finished the speaker cable from the amp to the sub. Monoprice 12g cable, flextech covering, and Neutrik connectors. The angle connector is the sub end.


    I moved my HSU VTF-15H out of the room and placed this bad boy in the same exact spot. It's actually shorter and not as deep; however, it's not moving... as it's a keeper. I pre-drilled the mounting holes, stuffed it with about 4 pounds of poly fill and used hex head screws to mount the driver to the box. I misplaced the screws I bought for the Neutrik connector, so it's just pressure fit for now, but it's not going anywhere. I want to raise the cabinet off the floor, so the hunt for spikes or rubber feet is on, but I'm extremely happy thus far. Now I just need to dial it in with my MiniDSP and run DIRAC.

    IMG_6376.JPG IMG_6377.JPG

    More to come...
    MrBoat, Spankopotamus and neo2016 like this.
  2. Starting to build #2. :D

  3. It only take a few mins to glue and clamp these enclosures up, but the time to wait for the glue to dry simply kills me! :rolleyes:

  4. May I ask what router bit you used? Does it matter? I'm new to using a router. I'd like to match the cab to the baffle like you did. Can I just get any 1/2" roundover bit and it will work?
  5. Sure, no problem, I don't mind answering questions, so please feel free to ask away. Here's the bit I purchased:

    It's a 3/4 round over bit and I'm using the following router:

    Just take your time and make sure you use a mask as MDF dust is nasty. I use a shop vac attachment on the router to keep the dust under control. Make sure the shank of the bit fits your router before you buy.

    Based on a friend's recommendation, I've only purchased Whiteside bits as he's seen the bearings on cheaper bits fail after a few cuts, so like everything else, you get what you pay for. Another tip... before you start routing the edge on your cabinet, do some tests on piece of scrap. :cool:
  6. Awesome. Thanks a lot!
    LuisV likes this.
  7. No problem... glad I could help.

    Mission accomplished for today as the top panel is glued on. [​IMG] I'll let the clamps and glue do their magic over night and will remove the clamps around lunch time. If the weather holds out tomorrow, after work I'll bring it outside to give the top panel a light sanding and then I'll glue on the front baffle.

  8. Almost done with my speaker stands... lmao

  9. Sanded the enclosure, rounded the corners over and applied two coats of Duratex. Almost done...

    MrBoat likes this.
  10. I am torn about which way to build for the UM18, sealed or Mini-Marty? Please let us know which you liked better.
  11. I haven't built the Mini-Martys... well, not yet. :rolleyes: My issue is I'm not in a dedicated room, so once my wife saw me cutting and dry fitting the panels for a Mini-Marty, so told me no way, not in the living room; however, see was ok with the sealed enclosures. We're in the process of hunting for a new home and high on the priority list is a dedicated space, so that is when I'll build the Mini-Martys and will see which enclosure I prefer.

Share This Page